Telephone-exchange system.



H. P. CLAUSEN.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED MAR. 13 1915.

1 Q5%@?w Patented Jan. 29, 1918.

irritate HENRY 1P. CLAUSEN, MOUNT VERNON, NEW "YORK, ASSIGNOR, BY llllESl l'E AFaSltl-N IWIENTS, T WESTERN ELECTRIC COMPANY, INCORPORATED, A CORPORATIGN OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

To all whom it may concern Be it known that I, HENRY P. Cnnusnn, a citizen of the 'United States, residing at Mount Vernon, in the county of Westchester and State of New York, have invented cer- Y tain new and useful Improvements in 'lelephone-Exchange Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone exchange systems of the central energy type and has for its object the production of improved signaling means for such systems.

In accordance with one feature of this in vention, means are 'provided at a central officc, whereby after the calling subscrihers receiver has been restored to the switchhook, the calling subscriber may, by a subsequent removal of the receiver from the switchhoolr,

cause the operation of recall signaling-means at the central oflice, thereby indicating to the operator that another connection is desired,

In accordance with,another feature of this invention, means are provided at the central oflice whereby, after the answering plug" has been inserted in. the jack of a callingili'ne, signaling means are caused to operate it a listening key is not at once actuated and will continue to operate until the listening lreyis actuated;

This invention is illustrated in the accompanying drawing in which all ap aratus is shown 1n" its normal and unactuate position.

' terconnecting the subscribers stations.

There is shown in the drawing a telephone exchange. system containing one embodiment of thisinvention and comprising the usual subscribers stations, A andlB, and a cord circuit C located at the central ofice for irIr understood from a description of the operation of the system shown in the drawing,

, and it will be so described Supposing subscriber A wishes to converse with subscriber B, A removes his receiver" from the switchhook, thereby completing a circuit from battery 5, through one winding of line relay'l, contact 8 oi cutoil relay 9, 1

line wires 10 and 11, contact 12 of cutoil relay 9 and the other Winding of line relay 7 to battery'5; Current in this path actuates line relay 7, completing a circuit for line signallfil a The operator observing the line signal 13 Specification of Letters Patent.

inserts the answering plug in the jaclr indicated by line signal 13, thereby closing" a Patented Alana 22., role, a lication filed March 13,1915. semi no. laws i i 2 circuit from battery 25 throughcontact 26 t of relay 27, supervisory signal 28, resistance 2%, sleeve-contacts of answering plug and jack and Winding of outed relay 9 to ground. Current in this path actuates cutofi' relay 9,

severing the circuit of line relay 7, thereby eli'acing line signal '13. completed frombattery 50 through winding of relay 22, resistances 2-3 and 2e, sleeve con tacts of answering; plug ancljaclr and Wind ing' of cutofif'relay 9 to ground. Current in this path actuates relay 22 which opens its A circuit is also contact 21. The insertion of the answering plug also closes a circuitfrorn battery-1t through winding of rela 15, ring contacts or the answering plug an jack, line ,wires 10 and 11, and the tip contacts of jack and an swering plug to battery i l. it is to-be noted that relay operates before relay 1.5. current in this p'ath actuates relay 15 'which closes its contact 20 completing a circuit from battery it through contact 20 of relay 15, winding of relay 27, resistances I23 and 4 24C, sleeve contacts of answering plug and j aclr and winding'ol cutofi'relay 9 to 5 ound. :Currentin this path actuates' relay 2 which opens its contact 26 and closes contact 51.

' Closure of contact 51 completes a circuit from battery 25 through intermipter 52, winding otpilot relay 53, contact 51 ol relay 27, supervisory signal ,28, resistance 24, sleeve contacts of answering plug" and jack and winding of cutoll relay 9 "to ground Since the interrupter 52 is in'circuit with supervisory signal 28, this signal will tlash intermittently until listening key 30 is operated. Also pilot relay 53 will be intermittently energized, thereby intermittently closing the circuit of pilot signal 54iuntil listening key 30 is operated. The operator now operates listening lrey 30 and connects the operators telephone set across the talk ing' strands of the cord circuit and asks the desired number of the calling subscriber. in operating listening lacy 30,. contact 55 thereof is closed, thereby completing a path from battery 14, through contact 20 of relay 15, contact 55 of listening key 30, resistances 28 and 2 1i, sleeve contacts of the answering plug and jack, and winding of cutoff relay 9 to ground. The completion of this circuit short circuits relays 22 and 2'? which recontacts of the calling plug and jack and the? winding of cutoff relay 34 to ground. Current in this path operates supervisory signal 3'. and actuates cutolf relay 34, cutting line relay 35 from line wires 36 and 37. The operator now restoreslistening key 30.to its normal position and operates ringing key 38, connecting the source of ringing current 39 to' Bs line to operate the ringer -10 at f station 13. SllbSClllJQl 13, upon remoying his receiver from the switchhookin response to the operation of ringer "l0, completes a path for direct current from battery 14. The completion of this circuit operates relay 45 which completes a circuit from battery 14 through contact 46 of relay l5, resistances 4.7 and I33, sleeve contacts of the calling plug '30 and jack, and the winding of cutoti relay 34 to grpund. Resistance 47 shunts supervisory signal 32, *ausing this-signal to be efiaced.

Upon finishing the conversation, sub- -scribers A- and B restore their respective 35 receivers to the switchhooks, whereupon relays 15 and' release, permitting supervisory signals 28 and 32 to operate to ive disconnect si nals. If the o )erator is. s s

not busy, the answering and calling plugs 40 are removed fr'omthe Jacks and all apparatus returns to normal. Suppose, however, that. as is frequently the case durin busy periods, the operator does not immediately take down the connection, and suppose fur- 46 tlier that subscriber desires to immediately make another call. lle removes his receiver from the. switchhook, thereby causing supervisory signal 28 to intermittently flash, sigmt'yung to the. operator that sub- 50 scriber A. desires another connection. The

manner in which supervisory signal 28 is caused to [lush will now be describe 7 When the receiver at substation A is restored to the switchhook, upon the completion of the conversation, the release of relay l5 removes a short circuit from about relay 2'2, whereupon relay Bills actuated due to a tlow of current from battery 50 through the winding oi this relay. 'lheuactuation of relay 22 opens its contact 9.1,lhcreby removing a normal shortci'rcuit of relay '37. Upon the subsequent removal of the receiver at substation A from its'switchhook relay 15 is operated, completing a circuit from battery ll. through COI1-' 66 tact 20 of relay 1.), winding of relay 27, re-

sistances and 24, sleeve contacts of the answering plug and jack, and'the Winding of cutoit relay 9 to ground. Current in this path actuates relay whicli'opens its contact :26 and closes its contact 51. The closure of contact 51 completes a circuit from tor operates listening key 30. The. opcrzc tion of listening key 30 closes contact 55. thereby short-circuiting relay 2? which releases and disconnects the interrupter from the circuit licreinbc'fore traced. Since. the.

listening key. 30 is operated, the operator may communicate with subscriber and ascertain his wants.

In telephone systems heretofore used, the. operator, being quite busy at frequent inter- 'vals, often inserts the answering plug in the jacket a calling line and forgets to actuate the listening key, whereby the calling subscriber is delayed and annoyed by having to operate the switchhook to attract the atten tion ofthe operator. In a telephone system embodying the present invention, the unsatisfactory condition just mentioned is overcome and the subscriber obtains much better service, It will also be seen that should the operator, after ascertaining the wants of the calling subscriber, forget to insert the calling plug, or after inserting the calling plug, forget to rin the wanted subscriber, the calling subscriber may readily attract the attention of the operator by merely moving the switchhook down and then up, whereupon both the supervisory signal 28 and the. pilot. signal 54 will llash intermittently.

It. will be seen that by the use of the cord circuit embodying this invention the calling subscriber may, at any time utter the-an- S\\'t ring plug has been inserted into the jack of the calling line, and provided the listening key is in its normal position, cause the supervisory signal :28 and pilot signal (it to intermittently flash, thereby attracting the attention of the operator more readily than could otherwise. be done.

\Vhile only one calling and one called subscribers line is shown. for the sake of sim plicity, it is to be understood that many such lines may terminate at the central otiice and that each line may be multiplcd tothe various sections of the. switchboard. In this description several batteries have till Sli

l eeneet been referred to, but it is to he understood that a commombattery may be substituted therefor and such is the usual practice.

cult for interconnecting the lines, a signaling device, interrupter mechanism, an operating circuit for the signaling device including the interrupter mechanism completed upon connection of the link circuit with a calling telephone line, an operators telephone set, a listening switch for connecting the opera tors telephone set in eircuit with the connected telephone line, and means responsive to the actuation of the listening switch for interrupting the operating circuit.

2. In a telephone exchange system, a plurality of telephone lines, a link circuit for interconnecting the lines; a signaling device,

interrupter mechanism, a relay operating upon connection of the link circuit with a telephone line to include the interrupter mechanism in circuit with the signaling (leviee, an operators telephone set, a switching device for including the-operators telephone set in circuit with the connected telephone line, and means actuated upon the operation of the switching device for causingthe ole energization of said relay.

3. in a telephone exchange system, a plurality of telephone lines, a link circuit for interconnecting the lines, a signaling device, a circuit therefor, interrupter mechanism, a

relay operating upon connection of the lllllli. circuit with a telephone line to include the interrupter mechanism in circuit with the signaling device. a listening key, and theircuit completed upon the actuation ol 'the listening key to cause the deiinergi'zationpt' said relay. I

lln witness whereof, I hereunto subscribe my name this 12th day of MarchJA. l).,

- HENRY P. CLAUSEN. llitnesses: i

E. Ennnn, K. L. STAHL. 

